1. Field
The present disclosure generally relates to equipment used to fabricate composite parts, and deal more particularly with a vacuum bag used to compress composite part layups.
2. Background
Flexible vacuum bags may be used to process parts in a wide variety of applications. In the composites industry, vacuum bags are used to consolidate, laminate, mold or bond composite parts using a vacuum drawn within the bag to apply atmospheric pressure to the parts. The bag comprises a flexible membrane or diaphragm that may be an extruded polymer film such as nylon.
Polymer film type vacuum bags are typically not re-usable and must be discarded after each use, thus representing a recurring production cost. Reusable type vacuum bags are known which employ a rubber coated fabric or film, however these types of bags, which typically employ stiffening structures, are relatively complex, heavy and relatively expensive to fabricate. For example, reusable elastomeric type vacuum bags are fabricated using metallic stiffening frames. Separate bonding operations are required to attach the bag diaphragm, seal and frame to each other. Each component is fabricated separately, and the tooling used to produce the bags must be oversized in order to allow for shrinkage of the bag diaphragm during fabrication.
Accordingly, there is a need for an improved, reusable, integrally stiffened vacuum bag that reduces the number of steps required for its fabrication, while reducing weight and complexity of the bag.